Question

Three consecutive odd numbers who's sum is 40

Answer 1

Odd Numbers are all of the form 2x+1 where x is a Natural Number or zero.

So what you are asking for is some numbers n,m,p∈N∪{0} such that:

(2n+1)+(2m+1)+(2p+1)=40

Rearranging we get:

2(n+m+p+1)+1=40

But the number on the left is of the form 2x+1 where x is a Natural Number or zero. So it must be odd. But 40=2×20 is clearly even and so we have a contradiction.